Torque determining method



.SEARCH @UGM Jan. l, 1957 E. l.. DECKER TORQUE DETERMINING METHOD Filed March 19 INVEN-ToR. ME@ l. BECKE'Q,

Kim www United States Patent O TORQUE DETERMINING METHOD Elmer L. Decker, Long Beach, Calif., assignor to Martin- Decker Corporation, Long Beach, Calif., a corporation of Delaware Application March 19, 1951, Serial No. 216,323

Claims. (Cl. 73-151) This invention relates in general to the oper-ation of rotary well tools, :and in particular to a method of determining the torque developed in the operation of such tools.

It is an object of this invention to provide a method of determining the torque developed in :a rotary well tool, whereby the condition of the tool and the nature of the work being done may be ascertained in order that corrective measures may be Italten to obtain a more eicient operation ofthe tool.

`It is another object -of this invention to provide a method of determining the net torque developed in a well tool.

It is another object of this invention to provide a method of determining the torque developed in the drill string while the `drill string is positioned in a well with the Itool at or adjacent the zone at which it is to be operated. With this information, the extent and nature |of the hole friction or other factors developing critical drill string torque, may be ascertained and remedial measures taken to provide for a more cih-cient operation ofthe tool.

It is another object of this invention to provide a method of ascertaining the net torque developed in a drill string or similar operating means for a rotary well tool.

I-t is another object of this invention to provide a torque determining method by means of which the Well driller may quickly and with reasonable accuracy, ascertain the nature of the work being done by the tool, and whether the tool requires replacement, or remedial treatment of the Well or drill string should be effected.

With this infomation, steps may be taken so that an appreciable saving in -time as well as in material and labor costs may -be effected in the drilling, Teaming, milling, cutting and other well .treatments as carried out with rotary tools.

zlt is a further object of this invention to provide methods of the character described which may be carried out with various types of torque indicating means which have been and may be `applied to well drilling and well working apparatus.

This invention possesses many other `advantages and has other objects which may be made more easily apparent from a consideration of several embodiments of the invention.` For this purpose there are shown in the accompanying drawings several forms of apparatus with which this invention may be carried out, but it is to be understood that this disclosure is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

Fig. 1 is a diagrammatic view of one form of apparatus with which the method of -this invention may be carried out;

Fig. 2 is a fragmentary, schematic, sectional view, showing another form of apparatus with which the method hereof may -be practiced;

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lFig. 3 is a fragmentary, diagramma-tic view of another form of apparatus with which the method hereof may be carried out; and

Fig. 4 is an enlarged sectional View taken substantially on the line 4-4 of Fig. 3.

In carrying yout the method of this invention, a torque determining means is installed on well drilling apparatus or well treating :apparatus so that the torque developed in the rotary drill string or similar operating means for a Well positioned in la well will be shown by a gauge, located at the top of the well.

After the drill string and tool are positioned in the well, the method hereof requires that the tool be rendered inoperative. In the case of tools of the type which yare operative when rotated at :a given location or at the bottom of the well and are inoperative when moved out of the given location or above the bottom of the well, as with drilling and reaming tools Iand the like, it is apparent that they may be rendered inoperative in accordance with this method `by |changing the position thereof through yappropriate manipulation of the `drill string.

In such cases the ltool is positioned adjacent the zone at which it is to be worked, yand while thus rendered inoperative, is rota-ted at a rate at which it is deemed essential for eicient operation when the tool subsequently is disposed in a working position.

Other well tools may be rendered opera-tive or inoperative mechanically responsive to appropriate manipulation of the drill string or any means extending to the top of the Well, `without appreciable movement, or in fact any movement of the tools from the zone at which they are to ybe worked. Some of the tools of this type are rendered operative and inoperative according to uid pressure actuated means :associated therewith.

Thus, with the one class of tools, for example, drill bits, underreamers, rotary bottom tools, and the like, it is by the positioning thereof that they become operative and inoperative, Whereas with the other class of tools for example, milling t-ools, casing cutters, and the like, the operativeness is a matter of changing the condition thereof without requiring any appreciable change in position.

While rotating the inoperative tool in the well at the aforementioned rate, the operator notes at the gauge, the torque developed, this being the ltorque developed under the hole friction and all other loads :attending the operation of the drilling -apparatus `as a whole, and is not a true indication of the torque developed according to the Work done by the tool.

As it is desirable to ascertain the torque at the tool and to determine the work being done by the tool, also the condition of the tool and the condition of the well, these factors may be established according to the method hereof by the simple expediency of adjusting the torque indicating gauge to show a reading other than that indicated while the inoperative tool is rotated at the aforesaid given rate.

Preferably the dial of the gauge is adjusted to show a zero reading, after which the tool is rendered operative by the positioning thereof or by conditioning thereof as hereinbefore noted, whereby the gauge reading will indicate the torque developed at the tool and make it possible for the driller to ascertain the work done by the tool and what corrective measures, if any, should be taken to operate the tool more efliciently.

After the net torque readings are provided for according to this method, the driller at all times during operation of the tool may quickly and accurately ascertain the work done by the tool and the conditions in the well so that proper remedial steps may be taken in a manner which will provide for an appreciable saving of labor, time and costs.

It should be noted that the present invention includes a method of obtaining the torque developed in the drill string or similar means for operating a well tool, in other words substantially the net torque developed in the string.

In carrying out the method of determining the net torque in the drill string, the string with the tool to be operated thereby are positioned in a well with the tool at or adjacent the zone at which the tool is to be operated. Next the tool is rendered inoperative, either by changing the positions thereof or the condition thereof as previously described, and the string is then rotated at the desired R. P. M. while the tool remains inoperative.

The torque reading on the gauge of the torque determining means, shows the torque developed as a result of hole friction or any other friction factor in the well or the string, as the net torque of the string.

The magnitude of this torque reading enables the driller to determine the condition of the well bore or well casing, as the case may be, and makes it possible for remedial measures to be taken to put the well bore, the casing, or the string in such condition as will permit of an eicient operation of the well tool.

One form of apparatus with which the present method may be carried out, is diagrammatically shown in Fig. l of the accompanying drawing and comprises, a torque indicating means 5 operating oif the draw works chain A of rotary well drilling apparatus B. This chain drives the sprocket 6 on the shaft 6a for turning the table 7 operating the rotary drill string 8 in the well 9.

The tool 10 here shown is a drill bit which when at the bottom of the well under the weight of the string as shown in full lines is operative, but when raised, for example as shown in dot dash lines, is inoperative.

A cave-in is indicated at 11 in the well to show one way in which the friction developed by contact thereof with the drill string will be accounted for as a hole friction component in the reading of the torque gauge 12.

In this connection, it should be noted that the gauge 12 is subject to adjustment by any suitable means, as by shifting the dial 12a thereof, to show an olf true reading, such as a zero reading, when otherwise the reading would indicate a particular torque developed by the entire apparatus at a given rate of rotation of the string.

As here shown, the gauge dial 12a has a ring gear 12b xed thereto and driven by a pinion 12C which is turned by means of a knurled knob 12d accessible on lthe back of the gauge. Thus, the dial may be adjusted as hereinbefore noted, in accordance with this invention.

The gauge 12 as here shown is hydraulically operated by means of a hydraulic piston and cylinder sensing unit 15 connected by a pipe line 16 with the gauge. Operation of the unit 15 is eifected by means of a lever 18 pivoted as at 19 on a support 20 and connected as at 21 with the unit which in turn is connected with a base 22. A wheel 23 rotatably mounted on the lever 18 is disposed to engage the lower run of the chain 6 so that the lever will rock according to the tension of this run of the chain whereby the sensing element will respond and hydraulically actuate the gauge.

With reference to the foregoing description of the method of this invention, it will be apparent that the apparatus shown in Fig. 1 may be employed to carry out the method in an efficient manner.

Fig. 2 shows a cutting tool 24 for cutting a well casing 25 under the method hereof. This tool is provided with uid responsive means 26 for extending the cutter blades 27 from a retracted and inoperative position into an extended and operative position. The means Z6 is subjected to uid pressure directed down the well, it being unnecessary to raise or lower the drill string 28.

A suitable torque determining means (not shown) is provided at the top of the well in connection with the apparatus shown in Fig. 2, and is subject to adjustment in the manner of the gauge 12 or in any manner to accomplish the zero or similar setting step of the method hereof.

'Ihe tool 24 in Fig. 2 exemplijies that class of tools referred to in the foregoing description of this method, wherein the condition of the tool rather thanl the position thereof in the well, determines its operativeness.

Another form of torque determining apparatus with which the method hereof may be carried out is shown in Figs. 3 and 4. This,apparatus is applied to the shaft 29 driven by the sprocket 29a of a rotary drill rig such as shown in Fig. l.

In this apparatus, a sensing shaft 30 is mounted in a bushing 31 in a bore 32 of the main shaft 29. The inner end of the shaft 30 is in threaded engagement with the inner end of the bore in the main shaft 29, While the major length of the shaft 30 has a rotating fit in the bushing 31 by which latter the shaft is held against lateral movement.

The section modulus of the portion of the main shaft 29 housing the shaft 30, with relation to that of the shaft 30, is such that the torque force applied to the relatively tubular end of the main shaft will produce gyration, while the sensing shaft which is xediat its inner end to the relatively solid mass'of the main shaft, will be relatively devoid of any moment of gyration.

Thus, when torque force is applied to the tubular end of the main shaft 29, this end thereof will have a slight gyrating motion while the sensing shaft 30 remains relaltively motionless, although both shafts, in a broad sense, rotate in unison as driven by the sprocket 29a.

On the extended end of the sensing shaft is a cam disk 33 having a cam face forming a central apex 34 from opposite sides of which are arcuate and receding cam :surfaces 34a and 34b concentric with the axis of the shaft 30. The surfaces 34a and 34b are disposed so as to be moved toward or away from the discharge end of a nozzle 35.

The nozzle 35 is supported by a frame 36 fixed to the main shaft to rotate therewith, the nozzle being connected to a source of compressed gaseous fluid (not shown) such as compressed air and operating to direct a jet of the air against the cam surfaces 34a and 34b. A pipe 37 is connected with the nozzle 35 and rotatably supported by means of a coupling device 38 joining a supply pipe 39 to pipe 37.

A torque gauge 40 corresponding to the gauge 12 shown in Fig. 1, is connected in the pipe line 39 and will react to differential pressure developed in the line. The dial of this gauge is calibrated to indicate the torque in the drill string according to the air pressure in the line 39, and is adjustable for zero or other reading in the same manner as the dial in the gauge 12, having the same adjusting means thereon for this purpose, the adjusting means being omitted in Fig. 3.

Due to the load imposed on the drive shaft 29 and the presence in this shaft of less rigidity at the outer end thereof, a lag in rotational movement will take place between the cam disk 33 and the frame 36 supporting the nozzle 35. This lag will cause the discharge end of the nozzle to move relative to the cam apex 34 and surfaces 34a and 34b. According to the portions of the cam surfaces against which the airjet from the nozzle impinges, a variable back pressure will be created in the supply line 39. The magnitude of this back pressure will be shown on the gauge 40 which is calibrated to read in terms of torque developed in the drill string and operating parts therefor, such for example as shown in Fig. l.

It will now be apparent that the methods of this invention may be carried out with the torque determining mechanism shown in Fig. 3 as well as with that shown in lFig. 1 and in fact with any torque indicating means which is applicable to well drilling apparatus for operating rotary tools in wells.

I claim:

1. The method of determining the torque of a tool operated by the rotary drill string of well drilling apparatus while the tool -is positioned in a well, which consists in applying to the drilling apparatus a torque indicating means which will operate responsive to the torque developed in the drill string, positioning the tool in the well, rendering the tool inoperative in the well; rotating the drill string and tool while the latter is inoperative, at a rate at which the tool subsequently may be worked in the well; adjusting the indicating means to show a zero reading while the inoperative tool is rotated in the well; rendering the tool operative; and then rotating said string to operate the tool whereby the torque reading of the indicating means is according to the torque developed in the tool.

2. The method of determining the torque of a tool operated by the rotary drill string of well drilling apparatus while the tool is positioned in a well; which consists in applying to the drilling apparatus a torque indicating f means which will operate responsive to the torque developed in the drill string; positioning the tool in a nonworking position adjacent the zone at which it is desired to work the tool in the well; then rotating the drill string at a rate at which the tool subsequently may be worked at said zone; adjusting the indicating means to show a zero reading while the tool is rotated in said non-working position; positioning the tool for working at said zone, and then rotating said string to work the tool whereby the torque reading of the indicating means is according to torque developed in the tool.

3. The method of determining the torque of a tool operated by the rot-ary drill string of well drilling apparatus while the tool is working in a well, which consists in applying to the drilling apparatus a torque indicating means which will operate responsive to the torque developed in the drill string, positioning the string and the tool in the well, rendering the tool inoperative in the well, rotating the drill string and tool while the latter is in- 6 operative, at a rate at which the tool subsequently may be worked in the well, adjusting the indicating means to show a zero reading while the inoperative tool is rotated at said rate; then tending the tool operative whereby the torque reading of the indicating means is the net torque at the tool.

4. The method of determining the torque developed in a well tool operated by a rotary drill string of Well drilling apparatus and wherein a torque determining means indicates the torque developed in said string; which method includes the steps of rendering the tool inoperative in the well, rotating the tool in the well while inoperative, adjusting the indicating means to show a zero reading While the inoperative tool is rotated, then operating the tool in the Well whereby the torque indicated will be the net torque developed in the tool.

5. The method of determining the torque developed in a well tool operated by a rotary drill string of well drilling apparatus, in connection with which a torque indicating means operates a gauge to show the torque developed; which method consists in moving the drill string to render the tool inoperative at a position adjacent the zone at which the tool is to be operated in the well; rotating the drill string and tool while the tool is inoperative at said position, at a predetermined drilling speed; then adjusting the gauge to show a zero torque reading while the string and tool are operated at said rate; moving the string to position the tool for operation lat said zone and rotating the string and tool at said drilling speed.

References Cited in the le of this patent UNITED STATES PATENTS 958,172 Putenberger May 17, 1910 1,795,623 Thompson et al Mar. 10, 1931 2,137,530 Johnson Nov. 22, 1938 2,235,279 Bunker Mar. 18, 1941 2,528,883 Hayward Nov. 7, 1950 

